Search results for "PULP"

Wastewater treatment and reclamation : A review of pulp and paper industry practices and opportunities

2016

The pulp and paper (P&P) industry worldwide has achieved substantial progress in treating both process water and wastewater, thus limiting the discharge of pollutants to receiving waters. This review covers a variety of wastewater treatment methods, which provide P&P companies with cost-effective ways to limit the release of biological or chemical oxygen demand, toxicity, solids, color, and other indicators of pollutant load. Conventional wastewater treatment systems, often comprising primary clarification followed by activated sludge processes, have been widely implemented in the P&P industry. Higher levels of pollutant removal can be achieved by supplementary treatments, which…

Sequential biological and photocatalysis based treatments for shipboard slop purification: A pilot plant investigation

2019

This study investigated the treatment of a shipboard slop containing commercial gasoline in a pilot plant scale consisting of a membrane biological reactor (MBR) and photocatalytic reactor (PCR) acting in series. The MBR contributed for approximately 70% to the overall slop purification. More precisely, the biological process was able to remove approximately 40%, on average, of the organic pollution in the slop. Nevertheless, the membrane was capable to retain a large amount of organic molecules within the system, amounting for a further 30% of the influent total organic content removal. However, this affected the membrane fouling, thus resulting in the increase of the pore blocking mechani…

Analysis of pharmaceutical biodegradation of WWTP sludge using composting and identification of certain microorganisms involved in the process.

2018

Pharmaceuticals (PhCs) are organic contaminants that have been detected in wastewater, surface water, and soils throughout the world. The presence of 10 commonly used PhCs in Spain (azithromycin, benzylpenicillin, citalopram, fluconazole, fluoxetine, ibuprofen, irbesartan, olanzapine, telmisartan, and venlafaxine) was analysed at four wastewater treatment plants, and the changes in their concentrations during treatment were assessed. Although certain some PhCs were degraded in the treated water, their presence in sewage sludge increased in all cases. The sewage sludge was composted using rice straw to degrade the PhCs, and the composting efficiency was modified by changes in the relative C/…

2018

Reactivity is an important parameter when considering the chemical modification or dissolution of cellulose. Different pretreatment methods affect cellulose reactivity by decreasing its degree of polymerization (DP) and crystallinity. In this study, the molar mass of cellulose was decreased via enzymatic pretreatment. Three commercial endoglucanase-rich products were tested. The target was to reduce the viscosity of the pulp to below 200 mL/g and, thus, increase the reactivity of the cellulose. For comparison, cellulose was also pretreated with ozone, and the effects of each pretreatment method on crystallinity and monosaccharide composition of the resulting pulps were investigated. Both en…

New silica based adsorbent material from rice straw and its in-flow application to nitrate reduction in waters: Process sustainability and scale-up p…

2021

Abstract This paper shows a particular example to move to a sustainable circular economical process from valorization of rice straw ashes by developing a green synthesis for obtaining a useful sub-product. This strategy can palliate negative effects of the agriculture waste practices on the environment and also the obtained silica reduced nitrate content in waters. It is demonstrated that the silica synthesis developed at lab was scalable more than a hundred times with good results. Adsorption studies of nitrate in standards and real well waters at lab scale and scaling-up provided similar results. Adsorption values near to 15 mg/g for nitrate standards and 8.5 mg/g for well water were obta…

Composting of bio-waste, aerobic and anaerobic sludges – Effect of feedstock on the process and quality of compost

2011

In-vessel composting of three stocks with originally different degree of organic matter degradation was conducted for: (1) kitchen source-separated bio-waste (BW), (2) aerobic (AS) as well as (3) anaerobic sludges (AnS) from municipal wastewater treatment plant. Composting experiment lasted over a year. The highest activity of the process was in the BW compost. It was implied by the highest temperature, CO(2) release, ammonification and nitrification, intensive accumulation and removal of low-weight carboxylic acids (water- and NaOH-extractable). Between the sludges higher mineralization and CO2 release was in AnS, while ammonification and nitrification were higher in AS compost; no signifi…

The influence of solid retention time on IFAS-MBR systems: Assessment of nitrous oxide emission

2017

The aim of the present study was to investigate the nitrous oxide (N2O) emissions from a moving bed based Integrated Fixed Film Activated Sludge (IFAS) - membrane bioreactor (MBR) pilot plant, designed according to the University of Cape Town (UCT) layout. The experimental campaign had a duration of 110 days and was characterized by three different sludge retention time (SRT) values (∞, 30 d and 15 d). Results highlighted that N2O concentrations decreased when the biofilm concentrations increased within the aerobic reactor. Results have shown an increase of N2O with the decrease of SRT. Specifically, an increase of N2O-N emission factor occurred with the decrease of the SRT (0.13%, 0.21% …

Reliable method for assessing the COD mass balance of a submerged anaerobic membrane bioreactor (SAMBR) treating sulphate-rich municipal wastewater

2012

The anaerobic treatment of sulphate-rich wastewater causes sulphate reducing bacteria (SRB) and methanogenic archaea (MA) to compete for the available substrate. The outcome is lower methane yield coefficient and, therefore, a reduction in the energy recovery potential of the anaerobic treatment. Moreover, in order to assess the overall chemical oxygen demand (COD) balance, it is necessary to determine how much dissolved CH4 is lost in the effluent. The aim of this study is to develop a detailed and reliable method for assessing the COD mass balance and, thereby, to establish a more precise methane yield coefficient for anaerobic systems treating sulphate-rich wastewaters. A submerged anaer…

The role of EPS in the foaming and fouling for a MBR operated in intermittent aeration conditions

2016

Abstract This work investigates the causes of foaming and fouling in an Intermittent Aerated – Membrane BioReactor (IA-MBR) used for wastewater treatment. The experiment was divided into three periods with different aerated regimes expressed with different t aeration /t cycle ratio (Period I: 60 min/180 min, Period II: 80 min/180 min, Period III: 30 min/90 min). The advanced foaming tests used allow the study of the role of extracellular polymeric substances (EPSs) on foaming and fouling. In general, in the Periods I and II, good correlations between the EPSs and the Modified Scum Index without purification (MSI 0 ) and the Foam Power were observed. The results shown that the filamentous mi…

Precipitation assessment in wastewater treatment plants operated for biological nutrient removal: a case study in Murcia, Spain.

2009

The Murcia Este Wastewater Treatment Plant is the largest wastewater treatment plant in Murcia (Spain). The plant operators have continuously found pipe blockage and accumulation of solids on equipment surfaces during the anaerobic digestion and post-digestion processes. This work studies the precipitation problems in the Murcia Este Wastewater Treatment Plant in order to locate the sources of precipitation and its causes from an exhaustive mass balance analysis. The DAF thickener and anaerobic digester mass balances suggest that most of the polyphosphate is released during excess sludge thickening. Despite the high concentrations achieved in the thickened sludge, precipitation does not occ…